Yarra Valley Water, one of Australia’s largest water utilities, has built an innovative Waste-to-Energy facility, which provides an environmentally friendly disposal solution for commercial organic waste. The purpose-built facility sits next to an existing sewage treatment plant in Aurora, and generates enough biogas to run both the facility and the adjoining sewage treatment plant, with the remaining 70 per cent, enough to power 1500 homes, exported to the electricity grid.

Yarra Valley Water Managing Director, Pat McCafferty, said similar facilities have been successfully used throughout the world, including Europe and the US, but extensive research was needed to determine whether it would work in the Australian market.

“This facility has the potential to change the way we use and value our assets in the Australian water industry.

“Instead of treating the organics as waste, we’re treating it as a product with value that can be reused to create and capture methane gas, resulting in significant environmental and cost benefits.

“As well as helping to keep organics out of landfill, we are also helping to make recycling commercial organic waste easier and more affordable for businesses,” Mr McCafferty said.

The facility has the capacity to process up to 33,000 tonnes of organic waste each year, or approximately 100 tonnes per day, offering an affordable alternative to organic waste disposal at landfill.

Since operations commenced in June 2017, Yarra Valley Water has diverted more than 20,000 tonnes of organic waste from landfill and produced more than 5,000,000kWh of electricity.

At full production 8,600,000kWh of electricity will be produced. Yarra Valley Water aspires to generate 100 per cent of its energy requirements from renewable sources by 2025.

The organic waste is fed into an anaerobic digester (sealed vessel) where it is converted into methane or “biogas” in the absence of oxygen.

The process captures the methane before it hits the environment and turns it into renewable energy.

A by-product of the Waste-to-Energy facility process is “digestate” – a nutrient rich product which has the potential to be used as an organic soil nutrient or fertiliser.

Yarra Valley Water is currently undertaking trials in relation to several commercial opportunities.

“The Waste-to-Energy project was born out of our desire to reduce our business costs and pass the benefit back to our customers.

“Water utilities can be high energy users, especially through our production, distribution and treatment processes,” Mr McCafferty said.

“As high energy users that are also impacted by climate change, we have multiple drivers to be a part of the solution.

“Victorian households and businesses generate more than two million tonnes of organic waste each year, almost half of which ends up in landfill. Communities and businesses have made it clear they want more opportunities to reduce the amount of waste that ends up in landfill.”

This facility alone produces about a quarter of Yarra Valley Water’s entire energy needs.

In reducing the energy demands of the adjoining sewage treatment plant and by exporting energy back into the grid, it has helped reduce both Yarra Valley Water’s and Victoria’s greenhouse gas emissions, contributing to a healthier environment and community.

Providing a solution fit for Australian conditions

Actively diverting organic waste from landfill extends the life of existing landfill sites, while the significant revenue and cost savings Yarra Valley Water receives from gate fees and the energy market contribute to keeping customers’ water bills affordable.

“Projects like this don’t happen without an enabling culture that supports achievement and innovation – and a way of thinking that sees what we do, inside of a bigger picture and broader community impact.

“This facility is the start of an exciting new chapter for the Victorian water sector in renewable energy production and waste to address the challenges our communities face,” Mr McCafferty said.

“One of the challenges we faced was ensuring that the technology was adaptable for the Australian climate and the local commercial market.

“Designing the plant to cope with Melbourne’s highly variable climate, the tank membranes needing to work in temperatures as low as 2ºC and as high as 45ºC, was a vital issue which needed to be overcome.

“This problem was solved by adapting the established European model to meet Australian standards, as well as the water industry’s extremely high safety and environmental expectations.

“Another challenge was sourcing the waste to make sure that we had a steady flow to power the facility.

“We identified gaps in the management of organic wastes, conducted an international search of how this could be done better, and then moulded a business case to deliver a viable, cost-effective solution.

“We also made a conscious decision to separate the facility from our core business and rebranded the facility ReWaste to allow more flexibility and commercial freedom to operate within the competitive waste industry.”

The number of businesses looking for a sustainable alternative is far larger than Yarra Valley Water first realised, particularly once other types of organic wastes (such as liquid wastes, sludges and packaged food) are considered.

The market for organic waste disposal in Melbourne is enormous with few market solutions available, making the utility’s offering a sought-after alternative to landfill.

The success of the ReWaste facility shows that environmental projects can be commercially viable. It challenges the role water companies play in reducing the impacts of climate change and building a sustainable future.

Utility Journalist

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